Diverse restriction fragment length polymorphism patterns of the PCR-amplified 16S rRNA genes in Aeromonas veronii strains and possible misidentification of Aeromonas species

Abstract

Restriction fragment length polymorphism analysis after PCR amplification (RFLP-PCR) of the 16S rRNA gene has been previously proposed as a rapid method to identify Aeromonas species. In the present study, the precision of RFLP-PCR was evaluated with 62 Aeromonas reference strains. The analysis revealed that Aeromonas veronii biovar sobria strains produce various patterns, possibly leading to its misidentification as an environmental species. For most other Aeromonas species little variation was noted. This study supports the usefulness of RFLP-PCR analysis to separate three clinically important species but also reveals possible misidentifications that necessitate further biochemical tests to validate the preliminary identification.

FIG. 1

RFLP patterns of the PCR-amplified gene encoding 16S rRNA from Aeromonas reference strains. Seven different RFLP patterns (A to G) were observed for AluI restriction digests. Three patterns (a to c) were observed for CfoI digests, and two patterns (d and e) were seen for MnlI. These patterns correspond to the patterns indicated in Table 2. The molecular weight standard (Std) was pBR322 DNA digested with MspI (New England Biolabs). The gels were photographed with Bio-print (version 6.21; Vilber Lourmat, Marne la Vallée, France), exported into Adobe Photoshop, and labeled in Macromedia Freehand 7.0.